An ovulation chart, also known as an ovulation predictor, is an organizational chart or calendar used to keep track of a woman’s fertility cycle. It can aid a woman who is trying to conceive a child by giving an estimate of what day of the month she is ovulating and most fertile. Ovulation charts can help determine which exact days conception is likely to be most successful.
Ovulation is the release of an egg that generally occurs about two weeks before a woman’s menstrual period, but can vary depending on the length of her menstrual cycle. Menstrual cycles are different for each woman but average between 21 to 35 days. To begin an ovulation chart, a woman has to first observe her menstrual cycle to determine its length. The first day of the chart begins on the first day of a menstrual period. A woman keeps track of how many days menstrual bleeding lasts, and then how many days pass until her next period begins in order to determine the exact length of her cycle.
Once a woman tracks her menstrual cycle on a chart or calendar, she can begin to predict the exact day she is ovulating. After an egg is released during ovulation, it must be fertilized within 12 to 24 hours or it deteriorates. Sperm can live in the body for around two or three days, so the most fertile days that need to be charted are the day of ovulation and around three days before.
Since there is no set length for an average menstrual cycle, there is no exact way to mathematically determine the day of the cycle when ovulation will occur. Ovulation can occur anywhere from the tenth day to the sixteenth day of a menstrual cycle. Instead of trying to calculate the ovulation day numerically, an ovulation chart can help a woman track the physical signs of ovulation to help her or her doctor determine the cycle day.
A physical sign that occurs prior to ovulation is the release of cervical fluid that is white with a thin, stretchy consistency, so a woman will record what day of her cycle she observes it. She can also use an ovulation prediction kit. Kits are available at drugstores and can measure the amount of estrogen in urine. High amounts of estrogen indicate ovulation, so a woman can use the results to pinpoint her ovulation day.
After the length of the menstrual cycle and day of ovulation are marked on the chart, it can be used to estimate the days intercourse or insemination is most likely to result in conception. The day of ovulation, as well as the three days leading up to it, are generally marked on the chart as the most fertile times of the cycle. Some women’s cycles are irregular, so an ovulation chart is intended to be kept until a woman or her doctor can determine a definite ovulation pattern.